Management of bacterial endocarditis

Most Eases of bacterial endocarditis involve infection with viridans strept ococci, enterococci, coagulase-positive staphylococci or coagulase-negative staphylococci. The choice of antibiotic therapy for bacterial endocarditis is determined by the identity and antibiotic susceptibility of the infecti ng organism, the type of cardiac valve involved (native or prosthetic) and characteristics of the patient, such as drug allergies. Antibiotic therapie s discussed in this report are based on recommendations of the American Hea rt Association. Treatment with aqueous penicillin or ceftriaxone is effecti ve for most infections caused by streptococci. A combination of penicillin or ampicillin with gentamicin is appropriate for endocarditis caused by ent erococci that are not highly resistant to penicillin, Vancomycin should be substituted for penicillin when high-level resistance is present. Resistanc e of enterococci to multiple antibiotics including vancomycin is becoming a n increasing problem. Native valve infection by methicillin-susceptible sta phylococci is treated with nafcillin, oxacillin or cefazolin. The addition of gentamicin for the first three to five days may accelerate clearing of b acteremia. Infection of a prosthetic valve by a staphylococcal organism sho uld be treated with three antibiotics: oral rifampin and gentamicin and eit her nafcillin, oxacillin, cefazolin or vancomycin, depending on susceptibil ity to methicillin. Vancomycin is substituted for penicillin in patients wi th a history of immediate-type hypersensitivity to penicillin.